For many years chlorine has been used to facilitate the processing of various organic compounds to obtain a variety of useful products. Organic compounds whether intentionally incorporating chlorine or by carrying a chlorine containing by-product may generate hydrochloric acid upon burning.
Among various halogenated products which are now restricted for production or which are being eliminated include materials such as chlorinated biphenyl, dioxin, and various ozone depleting materials such as chlorofluorocarbons propellants. More innocuous sources of organochlorine include products utilized as dispersants in motor oils. A dispersant is a compound which aids in keeping sludge from accumulating on engine parts. Due to environmental concerns, particularly in Europe, it has become desirable to eliminate or reduce the level of chlorine in products no matter how small the amount of the chlorine initially.
One potential solution to eliminating chlorine containing compounds is simply not to prepare any compounds in which the chlorine is an ingredient or which form a chlorinated by-product. The impracticalities of eliminating the production of all chlorine containing compounds worldwide should be readily apparent given the large amount of chemical production dependent upon the use of chlorine. Products which contain only small amounts of organochlorine and in which the chlorine does not impart a desired property to the composition may be treated to remove the chlorine. Such a process would have to be one which did not cause damage to the desired end product. Chlorine is in any event a desirable reactant in the chemical industry and is often utilized to promote or cause a faster reaction to give the desired end product.
Thus the present invention deals with methods of treating the organic chlorine containing compounds to reduce the chlorine content to acceptably low levels. The process may be modified such that the desired composition only contains a minor amount of organic chlorine and that the overall product's essential characteristics are not changed. In those products where the chlorine content is relatively high, the process is conducted to convert the underlying organic substrate to a relatively low chlorine content by-product.
The Finkelstein substitution was first described in Ber. 43,1528 (1910). Organic iodide compounds were obtained from the chlorides or bromides by treatment with sodium or potassium iodide in acetone solution. It was noted by Finkelstein that primary alkyl halides were the most reactive compounds and the tertiary were the least reactive. It was further observed that the treatment of 1,2-dihalides yields ethylenic derivatives. For further information on the Finkelstein substitution see The Merck Index An Encyclopedia of Chemicals and Drugs, 8th Edition, 1968.
U.S. Pat. No. 3,975,271 issued Aug. 17, 1976 to Saunier et al teaches water disinfection or sterilization is stated to be typically conducted with sodium hypochlorite. A difficulty noted by Saunier et al is that chlorine treatment alone often is ineffective due to the chlorine being tied up in the form of chloramines. Saunier, et al suggest that bromine and/or iodine may be helpful in treating water supplies.
Ross et al, in U.S. Pat. No. 4,049,382, issued Sep. 20, 1977 discuss a method for monitoring total residual chlorine in solution. The process of Ross is described as mixing a sample stream with a reagent stream containing a disassociated complex of alkali metal ion and iodide ion as well as an excess amount of iodide ion. The process is stated to take place such that iodide ion reacts with all residual chlorine in the sample stream and is converted to iodine. The activity of the iodine is then measured in the resultant stream with a first and second electrochemical potentiometric electrode.
The manufacture of various lubricating oil components is discussed in U.S. Pat. No. 3,231,587 issued Jan. 25, 1966 to Rense. Similar disclosures are found in U.S. Pat. No. 3,215,707 to Rense which issued on Nov. 2, 1965. The Rense patents generally discuss a process utilizing chlorine to obtain the reaction between a long chain hydrocarbon and maleic anhydride or maleic acid.
More recently, disclosures concerning the production of organo substituted maleic anhydride are found in U.S. Pat. No. 4,234,435 issued Nov. 18, 1980 to Meinhardt et al.
It is not believed that the foregoing publications are necessarily relevant to the present invention, however, they do indicate the state of the art concerning reactions of iodine, chlorine and various organic materials. Thus to the extent that any of the references cited herein are relevant to the present invention, they are incorporated herein by reference.
Measurements herein are understood to be approximate. Thus the word "about" may be introduced prior to any such measurement in the specification and claims. Ranges and ratios may be combined to further describe the invention. Temperatures given herein are in degrees Celsius, percentages are by weight, and pressures are in KPa gauge unless otherwise indicated. Where bromine or iodine is expressed to chlorine herein the ratio is in equivalents, e.g. I to Cl.
It is understood that the chlorine is chemically incorporated in an organic compound (hereafter organochlorine compound or chlorine-containing organic compound), and the bromine or iodine is in any form capable of generating elemental iodine, hydrogen iodide, bromine or hydrogen bromide.
The invention is particularly useful for lowering the chlorine content of chlorinated polymers. Without wishing to be bound by any theory, the invention is useful in treating chlorinated compounds such as polyisobutylene where the potential exists for the chlorine to be located on hindered secondary carbons or on neo primary carbons (a primary carbon bonded to a quaternary carbon). It is understood that when referring to polyisobutylene that the "pure" hydrocarbon and chlorinated polyisobutylene are used interchangeably and when only the chlorinated form is meant that the term polyisobutenylchloride is used. Similarly, when referring to polyisobutenylsuccinic anhydride, the "pure" anhydride and chlorinated polyisobutenylsuccinic anhydride are included, and when only the chlorinated form is intended, the term chlorinated polyisobutenylsuccinic anhydride is used.